THE OTHER EBOLA SCARE
Chimpanzees need protection too, but who can test the vaccine?
Anew study has shown great promise for an oral Ebola vaccine for chimpanzees and gorillas. But limits on testing are hampering the effort.
Here’s a closer look at the attempt to help save humans’ closest relatives:
Great Apes and Ebola The Ebola outbreak of 2013-16 highlighted the devastation of this virus. The hemorrhagic fever claimed the lives of 11,000 people, mostly from West Africa.
But what many may not know is that Ebola has also decimated our closest relatives: chimpanzees and gorillas. Ebola is estimated to have killed one-third of the world’s gorillas in the last three decades, and thousands of chimpanzees. Both species are now classified as endangered, with 300,000 chimpanzees and 95,000 gorillas. Commercial poaching and habitat loss has also caused a decline in the population of wild apes. The spread Ebola has no known cure. It is fatal in roughly 50 per cent of human cases and symptoms include high fever, bleeding and central nervous system damage.
Fruit bats are believed to be the normal carrier of Ebola, able to spread it without being affected.
The virus then spreads by direct contact with body fluids, such as blood, of an infected animal. People become sick through contact with infected gorillas or chimps, or their carcasses, or through eating infected bush meat. New vaccine for apes A new oral Ebola vaccine could help save the world’s gorillas and chimpanzees.
A trial of oral and injected vaccines on 10 captive chimpanzees at a research centre at the University of Louisiana Lafayette showed promising results for both.
The chimpanzees developed immunity for Ebola, and suffered no side effects, said Dr. Peter Walsh, a biological anthropologist at the University of Cambridge who conducted the trials. (Experimental trials of Ebola vaccines on humans have also been highly effective, according to a major trial in Guinea.) Chimp vaccine The Ebola vaccine for chimps is made of a weakened rabies virus — used in oral vaccines for animals — with an added gene for the main surface glycoprotein from the Ebola virus.
The vaccine was invented by Prof. Matthias Schnell’s lab at Thomas Jefferson University in Philadelphia.
The live rabies vaccine has been used in hundreds of millions of baits around Europe to fight rabies in foxes.
Asimilar approach in foods the apes like to eat could be by far the most effective way to deliver the vaccine in the wild.
The controversy However, controversy surrounds the chimp vaccine.
Recent changes in U.S. law mean biomedical testing on chimpanzees is no longer legal.
These reforms, which animal welfare groups have championed, could end up hurting chimpanzees and gorillas in the wild, as all vaccines must first be tested on animals in captivity.
Walsh says this is a shame. “At this point, the threat to chimps in the wild is so great that we need to accept that there will be some cost borne by some in captivity,” he said in an interview.
“If we don’t make those tough decisions, it will help push chimpanzees ever closer towards extinction in the wild.”
What’s next? The researchers hope to press ahead with some limited vaccine trials in wild chimps in Africa. “We will try to put the vaccine in something sweet, something fruity, that they like to eat,” Walsh said.
In the future, the vaccine could be a model to counter other diseases that infect ape species in the wild, including respiratory viruses that humans can pass on to them.
“We will try to use the Ebola vaccine to leverage more general disease prevention,” Walsh said.